[dsymutil] Better support for symbol aliases

This patch adds logic to follow a symbol's aliases when the symbol name
cannot be found in the current object file. It checks the main binary
for the symbol's address and queries the current object for its aliases
(symbols with the same address) before printing out a warning.

Differential revision: https://reviews.llvm.org/D38230

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314198 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed